Question on Poisson

The number of serious faults on a randomly chosen 1km stretch of motorway has a Poisson distribution of mean 2.1. The random variable X km is the distance between successive serious faults on the motorway.

The number of serious faults on a randomly chosen 1km stretch of motorway has a Poisson distribution of mean 2.1. The random variable X km is the distance between successive serious faults on the motorway.